What is the purpose of the load factor in a hashmap?

The load factor of a HashMap is a parameter used to measure the density of data stored in the HashMap, indicating the level at which data is stored in the HashMap. The purpose of the load factor is to set a threshold in the HashMap, so that when the data stored in the HashMap reaches this threshold, the HashMap will automatically resize itself to ensure performance and efficiency.

The default value of load factor is 0.75, which means that when the data stored in HashMap reaches 75%, HashMap will automatically resize. The choice of load factor can have an impact on the performance of HashMap. If the load factor is set too high, it may lead to data being stored too densely in HashMap, potentially increasing hash conflicts and reducing query efficiency. If the load factor is set too low, it may result in frequent resizing of HashMap, increasing system overhead.

Therefore, when using HashMap, it is important to choose the appropriate load factor based on the actual situation to achieve the best balance between performance and space.